The continuous process by which water moves from Earth's surface to the atmosphere and back.
The process by which molecules of a liquid absorb energy and change to a gas.
The process by which a gas changes to a liquid.
Rain, snow, sleet, or hail.
The process of changing free nitrogen gas into a useable form.
The study of where organisms live.
The very slow motion of the continents.
The movement of organisms from one place to another.
Species that are carried to a new location by people.
The typical weather pattern in an area over a long period of time.